DU, JIANWEI; SHAO, YANLING; SUN, XIAOLING. On a relation between the harmonic index and the chromatic number of graphs. Utilitas Mathematica , [S. l.], v. 111, 2019. Disponível em: https://utilitasmathematica.com/index.php/Index/article/view/1405. Acesso em: 7 may. 2026.